Though the deal would be new CEO Joseph Ripp’s first big acquisition, the insider said it has been in the works for some time now, pre-dating his appointment. Ripp began his CEO run in early September.

The deal was born out of necessity for American Express; due to new banking regulations, it is no longer allowed to participate in non-core businesses, like publishing magazines. Time Inc. and American Express’ magazines have been closely associated for nearly two decades, so its acquisition of the titles makes sense.

Time Inc. and American Express Publishing declined to comment. The New York Times was the first to report the news.

In March, Time Warner announced that it would spin-off its publishing division, Time Inc., into a separate company. In August, the company said the spin-off would be final in early 2014.